adaptation: return nil as no-op adjustment.

Don't create an empty adjustment a priori. Only create once
a plugin makes an adjustment to the container being created.
In particular, this should result in a nil adjustment if no
plugin touches a container.

Signed-off-by: Krisztian Litkey <[email protected]>

Author: klihub

pkg/adaptation/result.go

@@ -84,25 +84,7 @@ func collectCreateContainerResult(request *CreateContainerRequest) *result {
 		request: resultRequest{
 			create: request,
 		},
-		reply: resultReply{
-			adjust: &ContainerAdjustment{
-				Annotations: map[string]string{},
-				Mounts:      []*Mount{},
-				Env:         []*KeyValue{},
-				Hooks:       &Hooks{},
-				Rlimits:     []*POSIXRlimit{},
-				CDIDevices:  []*CDIDevice{},
-				Linux: &LinuxContainerAdjustment{
-					Devices: []*LinuxDevice{},
-					Resources: &LinuxResources{
-						Memory:         &LinuxMemory{},
-						Cpu:            &LinuxCPU{},
-						HugepageLimits: []*HugepageLimit{},
-						Unified:        map[string]string{},
-					},
-				},
-			},
-		},
+		reply:   resultReply{},
 		updates: map[string]*ContainerUpdate{},
 		owners:  resultOwners{},
 	}
@@ -249,6 +231,8 @@ func (r *result) adjustAnnotations(annotations map[string]string, plugin string)
 		return nil
 	}
 
+	r.initAdjustAnnotations()
+
 	create, id := r.request.create, r.request.create.Container.Id
 	del := map[string]struct{}{}
 	for k := range annotations {
@@ -284,6 +268,8 @@ func (r *result) adjustMounts(mounts []*Mount, plugin string) error {
 		return nil
 	}
 
+	r.initAdjustMounts()
+
 	create, id := r.request.create, r.request.create.Container.Id
 
 	// first split removals from the rest of adjustments
@@ -349,6 +335,8 @@ func (r *result) adjustDevices(devices []*LinuxDevice, plugin string) error {
 		return nil
 	}
 
+	r.initAdjustDevices()
+
 	create, id := r.request.create, r.request.create.Container.Id
 
 	// first split removals from the rest of adjustments
@@ -407,6 +395,8 @@ func (r *result) adjustCDIDevices(devices []*CDIDevice, plugin string) error {
 		return nil
 	}
 
+	r.initAdjustCDIDevices()
+
 	// Notes:
 	//   CDI devices are opaque references, typically to vendor specific
 	//   devices. They get resolved to actual devices and potential related
@@ -437,6 +427,8 @@ func (r *result) adjustEnv(env []*KeyValue, plugin string) error {
 		return nil
 	}
 
+	r.initAdjustEnv()
+
 	create, id := r.request.create, r.request.create.Container.Id
 
 	// first split removals from the rest of adjustments
@@ -509,6 +501,8 @@ func (r *result) adjustHooks(hooks *Hooks) error {
 		return nil
 	}
 
+	r.initAdjustHooks()
+
 	reply := r.reply.adjust
 	container := r.request.create.Container
 
@@ -545,6 +539,8 @@ func (r *result) adjustResources(resources *LinuxResources, plugin string) error
 		return nil
 	}
 
+	r.initAdjustResources()
+
 	create, id := r.request.create, r.request.create.Container.Id
 	container := create.Container.Linux.Resources
 	reply := r.reply.adjust.Linux.Resources
@@ -709,6 +705,8 @@ func (r *result) adjustCgroupsPath(path, plugin string) error {
 		return nil
 	}
 
+	r.initAdjustCgroupsPath()
+
 	create, id := r.request.create, r.request.create.Container.Id
 
 	if err := r.owners.claimCgroupsPath(id, plugin); err != nil {
@@ -726,6 +724,8 @@ func (r *result) adjustOomScoreAdj(OomScoreAdj *OptionalInt, plugin string) erro
 		return nil
 	}
 
+	r.initAdjustOomScoreAdj()
+
 	create, id := r.request.create, r.request.create.Container.Id
 
 	if err := r.owners.claimOomScoreAdj(id, plugin); err != nil {
@@ -739,6 +739,12 @@ func (r *result) adjustOomScoreAdj(OomScoreAdj *OptionalInt, plugin string) erro
 }
 
 func (r *result) adjustRlimits(rlimits []*POSIXRlimit, plugin string) error {
+	if len(rlimits) == 0 {
+		return nil
+	}
+
+	r.initAdjustRlimits()
+
 	create, id, adjust := r.request.create, r.request.create.Container.Id, r.reply.adjust
 	for _, l := range rlimits {
 		if err := r.owners.claimRlimits(id, l.Type, plugin); err != nil {
@@ -751,6 +757,73 @@ func (r *result) adjustRlimits(rlimits []*POSIXRlimit, plugin string) error {
 	return nil
 }
 
+func (r *result) initAdjust() {
+	if r.reply.adjust == nil {
+		r.reply.adjust = &ContainerAdjustment{}
+	}
+}
+
+func (r *result) initAdjustAnnotations() {
+	r.initAdjust()
+	if r.reply.adjust.Annotations == nil {
+		r.reply.adjust.Annotations = map[string]string{}
+	}
+}
+
+func (r *result) initAdjustMounts() {
+	r.initAdjust()
+}
+
+func (r *result) initAdjustEnv() {
+	r.initAdjust()
+}
+
+func (r *result) initAdjustHooks() {
+	r.initAdjust()
+	if r.reply.adjust.Hooks == nil {
+		r.reply.adjust.Hooks = &Hooks{}
+	}
+}
+
+func (r *result) initAdjustLinux() {
+	r.initAdjust()
+	if r.reply.adjust.Linux == nil {
+		r.reply.adjust.Linux = &LinuxContainerAdjustment{}
+	}
+}
+
+func (r *result) initAdjustDevices() {
+	r.initAdjustLinux()
+}
+
+func (r *result) initAdjustResources() {
+	r.initAdjustLinux()
+	if r.reply.adjust.Linux.Resources == nil {
+		r.reply.adjust.Linux.Resources = &LinuxResources{
+			Memory:         &LinuxMemory{},
+			Cpu:            &LinuxCPU{},
+			HugepageLimits: []*HugepageLimit{},
+			Unified:        map[string]string{},
+		}
+	}
+}
+
+func (r *result) initAdjustCgroupsPath() {
+	r.initAdjustLinux()
+}
+
+func (r *result) initAdjustOomScoreAdj() {
+	r.initAdjustLinux()
+}
+
+func (r *result) initAdjustRlimits() {
+	r.initAdjustLinux()
+}
+
+func (r *result) initAdjustCDIDevices() {
+	r.initAdjust()
+}
+
 func (r *result) updateResources(reply, u *ContainerUpdate, plugin string) error {
 	if u.Linux == nil || u.Linux.Resources == nil {
 		return nil